Does anyone here have any experience with a bass-reflex system that uses a horn at the outer end of the port? Particularly retrofitting a horn to an existing system.
Maybe even a horn on *both* ends of the port. That'd be interesting.
Maybe even a horn on *both* ends of the port. That'd be interesting.
Hi Graham,
That imagination of yours never takes a rest does it?
Using a horn for a port would be similar to using a flared port. The horn would be too small to have any real effect at the operating frequencies of the port.
That imagination of yours never takes a rest does it?
Using a horn for a port would be similar to using a flared port. The horn would be too small to have any real effect at the operating frequencies of the port.
No port with horn, but not far. My Altec A7 like Loudspeakers as far as i understand are portet boxes below ca. 150Hz. These speakers are not really famous for bass response. Measurement of the box standing free in room shows something like bass from 60Hz up. Placed in the rooms corner (= horn) i have bass form about 40Hz upwards. So i think about building a room with 2 suitable corners to avoid subwoofers.
http://home.tu-clausthal.de/~tpa/VotT/IMAGE0056.JPG
http://home.tu-clausthal.de/~tpa/VotT/IMAGE0056.JPG
I'm imagining 😉 using a BIG flared port, maybe 1 or 2 metres long. Actually, now I think of it, the speaker box would be like the compression chamber, only much bigger than usual.roddyama said:
What I really want to do is put a big funnel on the port hole of my sub to get super-duper efficiency over a necessarily limited range of frequencies. Or should I just shove it over the front of the driver instead? Or have both the driver *and* the port hole talking into the small end of the horn?
/Circlotron - making horn experts groan for sure.
Circlotron said:
I would try this first, from my experience in car audio, where many vehicles effectively horn load the subwoofers and vented enclosures have high efficiency there.
I would also initally set the port tuning frequency a bit higher than you would in a standard vented box, also from my experience in car audio, assuming you will be making a pretty large horn.
http://www.decware.com/wicked1.htm
1m horns are not bass useful.
not a horn but a waveguide
how would you calculate it? youd have to use horn software as a p ort cant be expanding like that and still be calculated.
Like a giant vero-vent the chambers are allowed to breath through the carpeting altering the impedance curve on the fly to enhance efficiency, and more importantly create a sympathetic diaphragm out of your floor!
1m horns are not bass useful.
not a horn but a waveguide
how would you calculate it? youd have to use horn software as a p ort cant be expanding like that and still be calculated.
Like a giant vero-vent the chambers are allowed to breath through the carpeting altering the impedance curve on the fly to enhance efficiency, and more importantly create a sympathetic diaphragm out of your floor!
Circlotron said:
isn't that what a rear loaded horn speaker does (the front radiates sound directly at the user and the rear picks up the efficiency [usually of the lower frequencies] by channelling the rear wave through a horn guide)?
A port in a BR type system operates on a different principle than a horn. A horn is an acoustic impedance transformer. The horn serves to increase the acoustic impedance on the compression driver so it can more effectively deliver its power to the room. A port holds a mass of air that resonates when excited at a particular frequency (tuning frequency) against the “spring” of the air in the box.
I’m implying that this idea won’t work, just that there are two different principles at work here.
I’m implying that this idea won’t work, just that there are two different principles at work here.
Its interesting how this morning I was thinking the exact same thing.
I'd suspect someone good with double BR boxes (MJK has a worksheet for them) could help on this one.
I'd suspect someone good with double BR boxes (MJK has a worksheet for them) could help on this one.
There Is Nothing New Under The Sun Dep't
It's been done before-half a century ago.
Abraham Cohen, in his book from the fifties, Hi-Fi Loudspeakers And Enclosures, showed designs of loudspeakers present at the time. One with a horn to enhance the output of the port was illustrated. The illustration is below.
It's been done before-half a century ago.
Abraham Cohen, in his book from the fifties, Hi-Fi Loudspeakers And Enclosures, showed designs of loudspeakers present at the time. One with a horn to enhance the output of the port was illustrated. The illustration is below.
Attachments
Could this effectively be the same thing that the "Snail Shell" (the car audio box that has caused so much controversy on this board recently) uses?
Watchya Port'in????
Bill Fitmaurice did some designs in speaker builder/ AudioXpress.
I built one or two of these and they indeed do work well. To the point they port the entire output of a driver/port output to give usefull output much below the port length/flare and ,outh size. Nifty and it would bve good to take a look at it.
Mark
Bill Fitmaurice did some designs in speaker builder/ AudioXpress.
I built one or two of these and they indeed do work well. To the point they port the entire output of a driver/port output to give usefull output much below the port length/flare and ,outh size. Nifty and it would bve good to take a look at it.
Mark
BAM:
Unfamiliar with the "Snail Shell" car enclosure. Searched and could not find anything. Any details would be helpful.
Unfamiliar with the "Snail Shell" car enclosure. Searched and could not find anything. Any details would be helpful.
keltic wizard=yes i have designed my horn with flat response .
however ive never modeled a horn THAT badly to have a response like you say...but i will try it.
keep mouth area constant but reduce length you say??
mcbeans hornresp does horns,i use it.
________________
the SNAIL SHELL is a magic box,2 versions of it,that is rampant and controversial on SOUNDDOMAIN.com and other car audio
sites.
i personaly cant see how a 6.5" can get such high SPL scores.
www.powered4sound.com
sells them.
Tline or whatever,u dont get that much gain for no reason
Basically,theres NO FACTS cos the guy hasnt released it..so u wont find anything but ppl asking questions,ppl who think theyk now,and ppl who give away clues but they probably dont know how it works 😛
i dont get hyped up over some random box that doesnt appear to do anything but gets HIGH SPl (apparently) and good Sound quality while scoring 18db too high in SPL comps...
SS1
ss2
ss3
ok enough about the snailshell,
😡
however ive never modeled a horn THAT badly to have a response like you say...but i will try it.
keep mouth area constant but reduce length you say??
mcbeans hornresp does horns,i use it.
________________
the SNAIL SHELL is a magic box,2 versions of it,that is rampant and controversial on SOUNDDOMAIN.com and other car audio
sites.
i personaly cant see how a 6.5" can get such high SPL scores.
www.powered4sound.com
sells them.
Tline or whatever,u dont get that much gain for no reason
Basically,theres NO FACTS cos the guy hasnt released it..so u wont find anything but ppl asking questions,ppl who think theyk now,and ppl who give away clues but they probably dont know how it works 😛
i dont get hyped up over some random box that doesnt appear to do anything but gets HIGH SPl (apparently) and good Sound quality while scoring 18db too high in SPL comps...
SS1
ss2
ss3
ok enough about the snailshell,
😡
As kelticwizard says, it's been done. However, the idea is seductive if you're seeking efficiency.
One point I don't think anyone has mentioned is that since the port is operative over a relatively short range of frequencies, you wouldn't be faced with the distortions you normally get when trying to make one horn cover multiple octaves. Unfortunately, the size inherent in one that will do you much good at low-ish port frequencies might be a booger in an average sized room.
But for midrange, now that might be interesting...
I've got a lathe and keep meaning to try my hand at turning a solid wood horn just for giggles. Never seem to get around to it.
Grey
One point I don't think anyone has mentioned is that since the port is operative over a relatively short range of frequencies, you wouldn't be faced with the distortions you normally get when trying to make one horn cover multiple octaves. Unfortunately, the size inherent in one that will do you much good at low-ish port frequencies might be a booger in an average sized room.
But for midrange, now that might be interesting...
I've got a lathe and keep meaning to try my hand at turning a solid wood horn just for giggles. Never seem to get around to it.
Grey
One thing I would like to add is that the irregular responses on these charts are probably not completely reflective of the response of a horn port enclosure. I get the impression that the ports were flared to a frequency that was drooping with a straight vent. In the frequencies where the radiation resistance was lacking, the flred port still acted like a port-it didn't lose it's output completely.
In short, I think they flared the port to add a little extra "oomph" a note or two lower than a straight vent would give. Remember, in a ported enclosure, the port output peaks at one frequency-above that it gradually yields to the cone. So I think the ported horn enclosure gives smoother response than you would guess from these charts.
In short, I think they flared the port to add a little extra "oomph" a note or two lower than a straight vent would give. Remember, in a ported enclosure, the port output peaks at one frequency-above that it gradually yields to the cone. So I think the ported horn enclosure gives smoother response than you would guess from these charts.
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